Bag filter



Y 3 0. EASTON, A. WATT-8: JnBUGHAN 4 BAG FILTER. No. 502,511.

(No Model.

(Nd Model.) 3 Sheets-Sheet 2. T. 0; EA'STON, A; WATT & J. BUCHANAN Jr.

- BAG FILTER. No. 502,511. H63 Patented Aug. 1, 1893.

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' 1 BAG FILTER- No. 502,511. Pjatehted Aug. 1, 1893.

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UNITED STATES PATENT @EEicE.

THOMAS O. EASTON, ALEXANDER WATT, AND JAMES BUCHANAN, J R, OF LIVERPOOL,ENGLAND.

BAG-FILTER.

SPECIFICATION forming part of Letters Patent No. 502,511, dated August1, 1893.

Application filed April 23, 1892. Serial No, 430.310. (N model.)

T0 on whom it may concern.-

Be it known that we, THOMAS OGILVY EASTON, ALEXANDER WATT, and JAMEsBUCHANAN, Jr., subjects of the Queen of Great Britain, residing atLiverpool, in the county of Lancaster, in the Kingdom of England, haveinvented certain new and useful Improvements in Filtering Plants forSugar, of which the following is a specification.

Bag filters, such as those known as Taylors filters, in use at thepresent time, consist of a casing or tank, generally rectangular inform, having a fixed top plate jointed on to a flange usually projectingfrom the inside surface of the casing at a lower level than the top ofthe casing, thus forming a shallow upper tank, into which the sugar orother liquor to be filtered is run. A series of bags open at one end andclosed at the other is fastened on to nozzles or bottles, as they aretechnically termed, which bottles are secured into the fixed top plateitself, or into nuts, fixed into the top plate; the bags are in this waysuspended vertically with the closed end down, in the interior of thechamber or casing, and the liquor runs into the top or shallow tank,then runs through the openings in the bottles and filters through thebags. The casings are provided with manholes or doors for access to theinterior of the chamber, and for the purpose of fixing in position thenozzles with clean bags attached, and also for removal of the same whenthe filter has finished operation, and requires replenishing with cleanbags for succeeding operations.

The disadvantages of this system are nu- ,merous and obvious, taking along time to filter the liquor, besides being severe and laborious workfor the men. After a time,,the bags become inoperative from their poresbeing clogged, and the filtering surface of the bags being quicklyreduced, and, toward the end, even before the bags are quite choked, theliquor only filters through very slowly, and eventually the supply ofthe liquor has to be stopped. The pores of the bags being choked, theliquor will not filter out, and a large quantity of unfiltered liquorremains in the bags. At present, in order to expel the remaining liquor,hot water is run into the top tank and into the bags,butit takes a longtime and requires a very large quantity of hot water to driveout theremaining liquor, and the resultant liquor is so diluted as to merelydeteriorate the product and increase the cost of obtaining it. Theproduct is deteriorated because it is found that weak solutions of sugarare much more rapidly and much more easily converted into glucose thanstronger solutions.

Now our invention is designed to obviate these evils generally, tolargely increase the quantity of liquor filtered through an equal numberof bags, or equivalent filtering surface, in a given time, to use a lessquantity of hot water, to save dilution of the liquor, thus preventingdeterioration of the product, facilitate the operations of working thefilters, economize space, reduce manual labor, and to expeditiouslytransfer the unfiltered liquor remaining in the bags into the chamber ofthe filter in use, or into another filter direct, or into a suitabletank or vessel provided for the purpose, without dilution of the liquor,in which it can be ire-treated and subsequently pumped or run out againfor subsequent filtration.

Referring to the drawings:Figure 1 is an elevation partly in section ofan apparatus; Fig. 2 a partial plan view; Fig. 3 a section of a singlefilter; Fig. 4 details of bottles and accompanying parts; Figs. 5 and 6details of joint between the'top tank and the filtering chamber; Fig. 7a plan view with cover partly removed from the filter; Fig. 8 analternative arrangement of filter, and Fig. 9 a sectional view of a bagand its attachment.

A A, are a series of filtering chambers arranged preferablyin two rows,side by side; B B, shallow tanks above these filters, the bottoms ofwhich tanks consist of the bottle plates; 0, a tray sometimes usedhooked on to the top tank when transporting a tank with all its tubesattached to it over the line of filters, this tray 0 being employed tocatch the drip from the bags and prevent them falling into the variousfilters en route; D D, the filtering bags; E E, the bottles; F, atraveling crane running on tracks suspended from the ceiling by bracketsG; H, metallic troughs, placed between lines of filtering chambers andbetween them and the Walls, serving as a floor IOC and also to catch anysplashings or drip. This fioor is preferably arranged with a slightdownward slope toward the end where the washing tank is situated.

The tank B, having for its bottom the bottle plate b, shown in detail inFigs. 3, 4; and 5, rests on the top edges of the casing A. Preterably,however, we groove the top of the casing with longitudinal groovings andthereon fix an india rubber plate I, having a longitudinal ridge on thetop as shown. Casing A is fitted, at the corners, with swiveling eyebolts J to tighten down the tank B in place, and the tank B is fittedwith eye boltsjin order to be more easily suspended to the travelingcrane.

The object of the india rubber plate Iis to form a sirup-tight seal. Itis, however, not indispensable, and, in place of this arrangement, thetop tank B could be provided with projections to guide it into itscorrect position, and could simply rest on the chamberv A. In place ofthe ordinary bags closed at one end and fastened to the bottle at theother, we use bags D, Figs. 1 and 3, about twice the length, inclosed inthe usual form of sheath, which is also about twice the ordinary lengthand has a bottle E E fastened at each end. One of these bottles Eisattached to the top in the usual manner. The other E is attached to thetop by screwing or otherwise fastening on to the neck the tube K, fromthe top side, which tube has a conical nut to fit and .joint into aconical hole or cut in the bottom plate of tank B. This tube rises abovethe level of the liquor in the shallow tank B, which is regulated by anoverflow. The tube acts as a nut to hold the bottle in its place withoutthe bottle being screwed into the bottom plate of tank B.

It will be obvious that this device could be varied in numerous ways;thus the tube K could be fixed and the bottle unscrewed by means of akey, or the tube could be a continuation of the bottle. The bag fixed inthis manner forms a loop, and the advantage of this arrangement is that,when the liquor is run into the shallow tank in the first instance, itenters the bags through the opening not provided with the tube;consequently, the air can at once rapidly escape through the otheropening to which the tube is attached above the level of the liquor inthe tank and no liquor enters through the end of the bag to which thistube is attached. By this means, the liquor descends through the onehalf of the looped bag and ascends the other half, until it reaches itsown level; moreover, as the liquor to be filtered passes down one sideor half of the looped bag and up the other, the tendency is for theslimy matter, which chokes the pores of the filtering bags and retardsfiltration, to deposit on the down half of the bag and at the bottom,and so leave the up bag comparatively clean, and, consequently, agreatcrquantity of liquor is filtered through equal surface and in a giventime. The bags can also be arranged in a group with one or more inletsfor liquor, the remaining bags all forming ascension filters as shown inFigs. 8 and 9 and hereinafter described. When the filter has beenrunning such a length of time as to make it practically inoperative forthe purpose of efficient and economic filtration, the usual dischargevalve or cook in the bottom of the casing, shown at S in Fig. 8,whichruns the filtered liquor into a gutter or pipe, can be shut off, and, byscrewing 01f the tube, one end of the bag will at once fall down andallow the unfiltered liquid contents to escape into the filter chamber,from which it can be run off by another outlet into a pipe or gutterleading to a suitable receptacle or tank providedfor the purpose. Theresult is our bags begin filtering and are emptied of the unfilteredliquor at the end of the operation in an extremely short time. The otheradvantages previously described are obtained by filling the casing withhot water. liquor can be washed out with a small quantity of water priorto the bags going to the final washing or scum room; or the bags may beemptied of their contents, and washed as hereinafter described.

The mode of working the apparatus may be described as follows:Thefilters generally stand on a floor in rows (or maybe suspended, aspositions demand) touching each other at the top and jointed togetherbetween the rows. The second flooring of metal trays H or fiat troughsis arranged nearthe top of the filter casings, covering the entire spacenot occupied by the filters. This flooring or troughing preferablyslopes slightly to the end where the washing apparatus is placed, and isarranged so that it can be washed down into the latter or into a liquortank and thus spilling on the fioor is prevented and the splashes anddrips are recovered. The traveling crane F above the filters is employedfor lifting the portable tops off and on the casings A, and, when thesedouble bags are used, the crane should be of sufficient height above thefilter to carry the tank, a set of double bags with their ends released,and a tray 0 hooked on to the bottom of these bags. In the drawings,Fig. l, the bags are shown in elevated position to commence operations,the tray 0 being shown in dots, and another shown in full on the top offilter B. At the beginning of the operations, the shallow tank B,forming the top of the filter, is placed in a convenient position by thecrane. The bags are attached thereto, the first row of holes beingsupplied with bottles screwed in, in the usual way; and, to the nextrow, theother bottles of the same set of bags are attached by screwingthe tube on to the top of thebottle from the top side of the shallowtank. This is continued until the entire sets of bags are fixed inposition. The cover or top of the filter, with all its bags attached, isnow carried by the traveling crane, as shown in Fig. l, and lowered intoposition on the top The sweet or sugar of the filter casing, themachined surfaces or the india rubber joint or seal making it tight. Thecrude liquor is then run into the shallow tank and descends through theopening into the bags to which no tubes are attached; at the end of thefiltering operation, the tubes are screwed off the bottles at the otherend, and the bags fall down, into the chamber as before described. Thefilter top is then attached by chains to the traveling crane and hoistedoff the casing, the bags hanging down vertically discharging theircontents into the casing of the filter as before described. The filtertop with the bags hanging from it is carried away to the washing room bythe aforesaid traveling crane. Previous to its be ing carried away,however the tray 0 is suspended by chains to the tankB immediately underthe lower bottles, so as, to catch the drip and prevent the latter fromfalling into the other tanks while traveling over these. The Whole isthen traveled over the other tanks B, and the thick liquor in the trayemptied into a liquor tank. The top and bags then pass on to a washingtank. By this arrangement the tray retains the drippings from thebagswhile passing over the other filters, and thus liquor of inferior classis prevented from falling into the other filters, which might be workinga superior class of liquor. In some cases, however, in place of allowingthe bags to empty into their own case A, the top with the bags looped upis lifted out of the filter casing and traveled by the crane overanother filter. The tubes are then unscrewed and the bags fall down anddischarge their contents into the tank B of this second filter. The topis then still farther lifted, the trayattached, as before described, andthe whole traveled to the washing room; or the top with the bags loopedup may be lifted out of the filter casing, and, with or without the trayattached, traveled by the crane over a liquor tank into which the bagswould be lowered, the tubes being unscrewed, the ends of the bagsfalling down, and the thick liquor emptied into the tank. The top isthen hoisted up and traveled over another tank where the liquor would bewashed out of the bags prior to their subsequent removal to the scumroom.

The bags, instead of being attached to the top, as before described, ateach end only, forming a single loop, can be of longer length and havemultiple loops, the inlet of the liquor of the tube end, as beforedescribed, being commonto the lot.

Figs. 8 and 9 show the arrangement of bags in a group.

The bags, instead of having each but one upright portion which receivesthe liquor at its upper end, and but one upright portion through whichthe liquor enters at its bottom, as represented in Fig. 1, have as seenin Fig. 8 one upright portion, indicated by D, which receives the liquorfrom the tray B, and numerousupright portions, indicated by D, all ofwhich are connected below with the upright portion D and receive theliquor at their bottoms. In this construction of Fig. 8, the bight orloop at the bottom of the bag, seen in Fig. 3, is replaced by aconnecting pipe N which is the equivalent of said bight or loop andperforms the same function, namely, that of connecting the lower ends ofthe respective upright portions of the bag. The portions of the bag arecoupled to the pipe N-by means of bottles m, as indicated in theenlarged sectional view Fig. 9. Of course more than one of the uprightportionsof the bag may receive the liquor at the upper end, it beingonly necessary to remove one or more of the pipes K to allow the liquorto enter. structed as seen in Fig. 8 cannot be conveniently emptied byreleasing its filling end from the tray B, the connecting pipe N isprovided with a screw plug P, which may be removed for discharging thebag. Indeed the substantially U-shaped bag we employ whether it has twoor many upright portions may be provided with simple means for emptyingit at the bottom, either by letting down one end, or by a plug, asdescribed.

We declare that what we claim is 1. A bag filtering apparatus comprisinga filtering chamber and a substantially U- shaped bag pendent therein,the extremities of the bag providing respectively an inlet for theliquor to be filtered and an air outlet sub stantially as set forth. 2.A bag for a filtering apparatus comprising two upright portionsconnected by a liquid passage at one end and at their other endsprovided respectively with an air escape passage and a liquid inletsubstantially as described.

3. In a filter, the combination with a filtering vessel A having a tankcover B of a filtering bag comprising two upright branches connected bya liquid passage at their lower ends, and at their upper ends secured tothe bottom plate of the cover and a tube K mounted in the upper end ofone of said branches and forming an air outlet substantially as setforth.

4:. An apparatus for bag filtration, comprising a chamber A, a removabletray-like cover B, for same, substantially U-shaped filtering bagssuspended from said cover, and means for emptying said bags while theyare still attached to the cover, substantially as set forth.

5. In a bag filter, the combination with the bottle plate I), of thebottle E screwed into it in the ordinary manner and a second bottle F.and tube K projecting above the liquor in the tank, the bag of onebottle being connected below with that of the other whereby the liquorshall run into the bag through bottle E and the air shall escape throughtube K.

6. In a bag filtering apparatus, the combination of a tankB to containthe liquor, abottle E, open to the liquor in the tank, a bottle E, opento the air above the liquor in the tank, whereat the air can escape, anda filter- As a bag con-' ed for receiving the liquor and the other foremitting the air, and the U-shaped bags D 15 substantially as described.

In testimony whereof We have signed our names to this specification inthe presence of two subscribing Witnesses.

THOMAS O. EASTON. ALEXANDER WATT. JAMES BUCHANAN, J NR.

Witnesses:

WM. P. THOMPSON, L. O. JOHNSON.

